Fix interpretation of / in META files (#1889)

Fix #1885

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

CHANGES.md

@@ -1,3 +1,13 @@
+1.7.3 (unreleased)
+------------------
+
+- Fix interpretation of `META` files containing archives with `/` in
+  the filename. For instance, this was causing llvm to be unusable
+  with dune (#1889, fix #1885, @diml)
+
+- Make errors about menhir stanzas be located (#1881, fix #1876,
+  @diml)
+
 1.7.2 (21/02/2019)
 ------------------
 

src/dune_package.ml

@@ -31,7 +31,12 @@ module Lib = struct
         ~foreign_archives ~jsoo_runtime ~main_module_name ~sub_systems
         ~requires ~ppx_runtime_deps ~implements ~virtual_ ~modules ~modes
         ~version ~orig_src_dir ~dir =
-    let map_path p = Path.relative dir (Path.basename p) in
+    let map_path p =
+      if Path.is_managed p then
+        Path.relative dir (Path.basename p)
+      else
+        p
+    in
     let map_list = List.map ~f:map_path in
     let map_mode = Mode.Dict.map ~f:map_list in
     { loc